2005 6.0 Runs Bad when cold
 

Hi, I've been trying to figure out the problem with my 6.0 for some time now, when started in the morning and cold outside, the truck runs like crap, feels like it's running only on a couple cylinders. I have 97k on the truck, just got it back from Ford to have the EGR cooler and Oil Cooler replaced, was loosing water, I though that was the reason, seems like when I first got it back, it ran good, but it was still warm outside. It takes a good 5 to 10 minutes for it to really warm up and start running good. All other starts from that point are good unless it sits all day. Any suggestions? One last thing, if I plug it in and start it the next morning, runs like a top. Thanks

It sounds like you have an injector or two going bad. Even just one injector can make it run pretty rough. You change your fuel filters enough?

I didn't think about the injectors, and no, I don't change then too often, as a matter of fact, it's been about a year now.

My 6.0 did that twice when I had it, it was injectors both times.

If you hurry, that should be covered under warranty. 3k miles to go. Time to take it in for a thorough checkup before warranty ends.

I had that problem also with the rough starts in cold weather. Ford replaced the FICM in my case but it still did not resolve the issue. It wasn't until i switched to 5w40 synthetic mobil 1 turbo diesel formula that my issue was resolved. The 15w40 had to high of a viscosity. And since you had the cooler etc. Replaced that means that ford drained and filled your trucks oil. What do you normally run in it?

If you search the tech folders in this forum there are some videos of trucks with bad injectors. So you can compare that truck to yours before you take your truck into the dealer.

injectors or ficm

Check your oil level. My 7.3 will run like crap when it is cold and my oil level is low. Once the oil gets warm and expands it runs better. The fuel injectors are controlled by oil/oil pressure. So if oil is low they will not inject well or something like that. Hope this helps.

Precisely why I said to check what oil your engine has in it. Ford would use the Motorcraft 15W40 which is to heavy for cold climates. There is even a TSB for the 6.0's regarding oil viscosity and ambient air temperature. And of course your it's also in either your owner's manual or your engine manual.

before you spend to much. i had the same trouble with my 03 and it only needed to be reprogrammed under recall. if it is injectors they would be rough all the time. the oil could be it but maybe call the dealer first. i went in with the engine light on and they told me that first and fixed it before they took care of the engine light which was a sensor unrelated to the rough idle.

As bpounds mentioned, your truck is still under warranty. With only 3k miles to go, I'd hold off doing any experimenting to try fixing the problem yourself.

Let the dealer work on it while it is still on their dime.

Lou Braun

I have an 05' as well. I was running 15w40 in and it started up as rough as can be. Only had it in there for 400 miles and I switched to Rot 5w40 syn. It was like night and day. Just went and got the new flash as well. Just cranked it up this morning at 20 degrees and it ran as smooth as you can get. The new flash addresses the cold start issue. The 05' has a recall on the ebp sensor as well. If you haven't gotten that, you might want to . They will flash it for you then. Might want to consider it. Hope all works out for you. Later,Eric

So the truck starts good when it's warm out. If it's cold it has to warm up. And if it's plugged in all night it runs fine in the cold morning. Sounds like the oil is to heavy for the cold weather. So let me explain oil. Multi weight oils are made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number (15) indicates the viscosity of the oil at a cold temperature ( W= winter), while the second number indicates the viscosity at operating temperature (40). So if you're using 15W in your diesel in the cold and start your truck the oil is very thick like honey vs. 5W which will be thinner like water at cold start but once at operating temperature will still be 40weight just like the 15W40..... The viscosity rating is basically just the fluids resistance to flow.

I've been running the 15/40 Motorcraft Diesel oil. It's interesting you mention about the oil, when I did my last oil change, it was several quarts low, the dealer changed it last when they did the egr cooler etc. I'm taking it in the morning to get it looked at